Beat the eggs until frothy. Sift flour and salt onto the egg mixture and mix. Stir in milk and mineral water. Let the pancake batter rest for about 20 minutes. In the meantime, clean, wash and halve the plums, remove from the stone and cut into slices. Stir yoghurt, vanilla sugar and cinnamon until smooth.
Heat the oil in a frying pan, place 1/4 of the plums in the pan, add 1 ladle of dough and bake at medium heat for about 2 minutes. Turn from time to time. Fry 3 more pancakes one after the other. Arrange the pancakes on plates, add a teaspoon of yoghurt and serve sprinkled with pistachios. Serve the rest of the yoghurt separately. Decorate with lemon balm as desired